Hi Carly, if you are just starting out and want to learn Wordpress to build blog sites or a website for your business-- it is free for you to download and install the open source framework, provided you have the technical knowledge in subscribing to a web hosting account, registering a domain name, and setting up the web server. It sounds like a lot of work (and it is) just to want to start playing with all the free themes, plug-ins available!
However, the trend is for students, beginner Wordpress developers and new business owners to sign-up to Wordpress hosting where everything is already set up for you-- you won't have to worry about much programming, or setting up servers.
You might want to check out a site like YoloPress (www.yolopress.com) where they have tutorials with step-by-step screenshots on setting up your own website. The tutorials are free, creating an account is free, however when you launch your site there is a monthly fee. The service is fast, and secure.
For the tutorials:
Resource Center: https://www.yolopress.com/wordpress-how-to-resource-center/
Creating an Account: https://www.yolopress.com/2014/03/07/create-yolopress-account/
Website Checklist: https://www.yolopress.com/2014/03/05/wordpress-website-builder-checklist/
...plus many more tutorials to embed photos, videos, maps etc.
Good luck.